javascript-- get the number of a page for each label

Gets a page number for each label

document.getElementsByTagName ( '*' ) - get all the labels.

var obj = document.getElementsByTagName('*');
    var len = obj.length;
    var tagNameObj = {};
    for(var i = 0; i < len; i++){
        if(tagNameObj[obj[i].tagName] == undefined){
            tagNameObj[obj[i].tagName] = 1;
        }else{
            tagNameObj[obj[i].tagName] += 1;
        }
    }
    console.log(tagNameObj);